Since borders are opening up and vaccines requirements easing I thought I'd share my experience on Allure of the Seas getting tested for travel to Canada after the cruise.
In my case my booking appears to be a standard one cruise (no B2B) US booking. This means that testing for me normally wouldn't be required. I had communicated with the guest services team before boarding given my unique scenario of not appearing to need a test yet actually requiring a PCR test for travel to Canada.